The photon-enhanced thermionic emission (PETE) generator is a semiconductor-based device converting both the photonic and thermal energies of solar radiation to electricity at a higher conversion efficiency than conventional photovoltaic cells. Typically a vacuum gap is required between the cathode and the anode, and the PETE device operates most efficiently at temperatures in excess of 200 degrees Celsius, the reference temperature for aircraft engine bleed air. Unfortunately, the electrical conversion process produces waste heat which is often not utilized in certain applications, such as in an aircraft that depends on solar energy for its operation or propulsion. For example, there may be a lack of synergy between the PETE generator and other systems consuming or generating energy on an aircraft. Also, the operating temperature may be unregulated which can reduce the conversion efficiency of the PETE, depending on an amount of incident solar radiation and the ambient temperature. Additionally, the vacuum gap can be expensive to include in the fabrication process.